Birthyear.html

<!DOCTYPE html>
<html>

<head>
	<meta charset="utf-8">
	<title>Birth Finder</title>
</head>

<body>
	<center>
		<form style="margin-top: 250px;">
			<input style="width: 300px; height: 28px; border-radius: 4px;" type="number" name="number"
				placeholder="Please type your age!" id="number" />
			<input style="width: 130px; height:32px; border-radius:4px" type="button" name="button" value="Birth Finder"
				id="button" />
			<center>
				<p style="background:black;color: white;" id="year">Year</p>

			</center>
		</form>
	</center>
	<script type="text/javascript">
		function calculate() {
			var number = document.getElementById("number").value;
			if (number == " " || number == 0) {
				alert("Please enter your correct age!");
				return;
			}
			var date = new Date().getFullYear();
			var birthyear = number - date;
			document.getElementById("year").style.display = "block";
			document.getElementById("year").innerHTML = "Hey, Your Birth Year is :  " + birthyear;
		}
		document.getElementById("year").style.display = "none";
		document.getElementById("button").onclick = function () { calculate(); }


	</script>




</body>

</html>